Vexxing…text widgets won't stick

I have 3.3.1 and the 2011 theme. I have not been changing that at all. I had widgets in place and working, but suddenly the text widgets have disappeared and dragging them back and re-entering them doesn’t work. I save them, but they are just gone again, both when I visit my blog AND behind the scenes. What could be going on? I did deactivate my plugins, but the problem continued. I would so appreciate some help.